I know you are looking for those magic words to say or the right button to press that will make this all go away and be back to where you were.
It does not work that way.
So this is a lot of hard work and self introspection.
You must LET GO and let her do the same things that you also must do.
You both do them separately - not together.
If she is depressed she must decide that she doesnt want that anymore. People that are depressed want to DENY that there is anything wrong with themselves and it must be someone elses fault. STOP TRYING to FIX HER.
You didnt break her and you can not FIX this.
You can only fix yourself and become the best YOU possible.
